ERCP (Endoscopic Retrograde Cholangio Pancreatography) is a minimally invasive procedure which allows the doctor to perform necessary treatments such as enlarging a bile duct opening, removing gallstones lodged in the bile duct, inserting a stent (drain) in the duct or taking a biopsy specimen.
A flexible fiberoptic tube, called a duodenoscope, is passed through the mouth, esophagus and stomach into the duodenum, which is the first part of the small intestine. The duodenoscope is a thin, flexible tube with a tiny video camera and light at one side of the tip. The papilla, which is an opening where the bile and pancreatic ducts empty into the duodenum, is visually identified. A small plastic tube, or cannula, is passed through the duodenoscope into the papilla. X-ray dye is injected through the cannula into the ducts. X-rays are then taken to study the ducts. Any necessary treatments can be performed at this time.
FIG. 1 is a diagram of the portion of the gastrointestinal tract which immediately surrounds the bilio-pancreatic system, and the bilio-pancreatic system itself, while FIG. 2 is a diagram of the cannula for injecting the dye. The catheter is inserted via the papilla into the ducts. The dye is injected using the cannulate of the catheter. There are different types of catheters, some of which, called sphincterotomes, are used for sphincterotomy, to enlarge the opening of the bile duct. This procedure is done with an electrically heated wire.
Additional tools which may be used include a biliary stent. If the X-ray images show a blockage in the bile duct, the doctor may place such a biliary stent inside the duct itself to help the bile drain into the intestine in the normal way. Other tools include a basket for removing stones from the bile ducts, and balloons, which may also be used for removing stones, and for opening stenotic portions of the bile ducts.
One drawback of this procedure is that the duodenoscope must be maneuvered by the physician according to images of the gastrointestinal system and/or papilla which are received from the camera and displayed on a video screen. The lack of direct visual feedback from the organ system is one factor which renders duodenoscopy a complex and difficult procedure to master. Such lack of feedback also increases the difficulty of hand-eye coordination and correct manipulation of the duodenoscopic device. Thus, duodenoscopy of the bilio-pancreatic system is a difficult procedure to both perform and to learn.
Currently, students are taught to perform such procedures according to the traditional model for medical education, in which students observe and assist more experienced physicians. Unfortunately, such observation alone cannot provide the necessary training for such complicated medical procedures. Students may also perform procedures on animals and human cadavers, neither of which replicates the visual and tactile sensations of a live human patient. Thus, traditional medical training is not adequate for modern technologically complex medical procedures.
In an attempt to provide more realistic medical training for such procedures, simulation devices have been developed which attempt to replicate the tactile sensations and/or visual feedback for these procedures, in order to provide improved medical training without endangering human patients. An example of such a simulation device is disclosed in U.S. Pat. No. 5,403,191, in which the disclosed device is a box containing simulated human organs. Various surgical laparoscopic procedures can be performed on the simulated organs. Visual feedback is provided by a system of mirrors. However, the system of both visual and tactile feedback is primitive in this device, and does not provide a true representation of the visual and tactile sensations which would accompany such surgical procedures in a human patient. Furthermore, the box itself is not a realistic representation of the three-dimensional structure of a human patient. Thus, the disclosed device is lacking in many important aspects and fails to meet the needs of a medical simulation device.
Attempts to provide a more realistic experience from a medical simulation devices are disclosed in PCT Patent Application Nos. WO 96/166389 and WO 95/02233. Both of these applications disclose a device for providing a simulation of the surgical procedure of laparoscopy. Both devices include a mannequin in the shape of a human torso, with various points at which simulated surgical instruments are placed. However, the devices are limited in that the positions of the simulated surgical instruments are predetermined, which is not a realistic scenario. Furthermore, the visual feedback is based upon a stream of video images taken from actual surgical procedures. However, such simple rendering of video images would result in inaccurate or unrealistic images as portions of the video data would need to be removed for greater processing speed. Alternatively, the video processing would consume such massive amounts of computational time and resources that the entire system would fail to respond in a realistic time period to the actions of the student. At the very minimum, a dedicated graphics workstation would be required, rather than a personal computer (PC). Thus, neither reference teaches or discloses adequate visual processing for real time visual feedback of the simulated medical procedure.
Similarly, U.S. Pat. No. 4,907,973 discloses a device for simulating the medical procedure of flexible gastro-endoscopy. The disclosed device also suffers from the deficiencies of the above-referenced prior art devices, in that the visual feedback system is based upon rendering of video data taken from actual duodenoscopic procedures. As noted previously, displaying such data would either require massive computational resources, or else would simply require too much time for a realistic visual feedback response. Thus, the disclosed device also suffers from the deficiencies of the prior art.
A more useful and efficient medical simulation device for minimally invasive therapeutic procedures such as endoscopy is disclosed in PCT Application No. WO 99/38141, by the present inventors and incorporated by reference as if fully set forth herein. The disclosed medical simulation device provides real time, accurate and realistic visual feedback of general endoscopic procedures, as well as realistic tactile feedback, so that the visual and tactile systems are accurately linked for the simulation as for an actual medical procedure.
Duodenoscopy of the bilio-pancreatic system would also benefit from such realistic simulation, involving both visual and tactile feedback which are provided in an accurate manner. Bilio-pancreatic duodenoscopic procedures feature many of the same principles as gastro-endoscopy, since for both types of endoscopic procedures, an instrument is inserted into a body orifice, and must then be guided through a tubular organ without direct visual feedback. In addition, the physician performing the procedure must be able to correctly interpret both the indirect visual feedback provided through a video monitor, as well as the tactile feedback through the instrument itself. Therefore, both types of duodenoscopy require the physician to receive “hands-on” manual training for the correct performance of the procedure.
In addition, bilio-pancreatic duodenoscopy has other features which differ from gastro-endoscopy. For example, bilio-pancreatic duodenoscopy may also involve the optional procedure of contrast dye injection into the bilio-pancreatic system. Thus, although bilio-pancreatic duodenoscopy shares many features with gastro-endoscopy, the former procedure must be separately simulated for accurate training and simulation.